This invention relates to improvements in antennas, and more particularly to antennas used as receiving antennas for space satellite signal transmissions.
Both the bearing and elevation of a space satellite relative to a receiving antenna is normally changing with time. Directional antennas have to be constantly moved in order to direct the antenna beam at the satellite. However, the present invention relates to a passive antenna which need not be moved in any way but relies instead on its response pattern to provide an acceptable output despite variations in elevation and bearing of the satellite.
Such an antenna ideally requires a circularly polarized hemispheric response pattern. Omni-directional type passive antennas have difficulty in achieving equal gain at all elevation angles because the projected receiving area of the antenna in the direction of the horizon is normally small.
An objective of the present invention is to provide a passive antenna arrangement in which the response pattern is a close approach to the ideal of a hemisphere.